The shaft to which a cam is attached

The shaft to which a cam is attached is known as a camshaft.

a shaft with cams distributed along cams's length

A camshaft is basically a shaft with cams distributed along cams's length.

the part of the engine that closes and opens the intake and exhaust valves

The camshaft is the part of the engine that closes and opens the intake and exhaust valves.

part of a vehicle's engine

A camshaft is part of a vehicle's engine.

one of the most important parts of a modern engine

The camshaft is one of the most important parts of a modern engine.

a rotating shaft with lobes

The camshaft is a rotating shaft with lobes, also called cams hence the name camshaft.

a component of the piston engine

The camshaft is a component of the piston engine.